Section  discusses cosmological parameters for the
base \(\rm {\Lambda CDM}\)  model. We demonstrate the consistency of the cosmological
parameters determined from various likelihoods, sky areas, temperature
and polarization combinations and also with different methods of
temperature foreground cleaning. We also revisit the consistency of
cosmological parameters determined from different multipole ranges.
Possible tensions with other astrophysical data are discussed briefly
in this section. One-parameter extensions to the base \(\rm {\Lambda CDM}\)  model are
discussed in Sect. . We do not present a
comprehensive analysis of extended models, but instead focus on the
parameters \(A_L\)  and \(\Omega _K\)  for which there were hints of
anomalies in PCP15 and PCP18. We also present results on the sum of
neutrino masses \(\sum m_\nu \) , the number of relativistic species \(N_\nu \) 
and the tensor-to-scalar ratio \(r\) , using our statistically most
powerful likelihood, combined with results from other experiments.
A comparison of our best fit \(\rm {\Lambda CDM}\)  cosmology with the power
spectra measured from ground based polarization experiments [1]}, [2]}
is presented in Appendix .
